OCTANE Speed Sandwich – Page 12

Day 1 Observations

Posted in OCTANE Speed Sandwich, ProbSevere, SPG2023 on June 12, 2023 by Kevin Thiel.

The one thing I found today from looking at PUB CWA, was that the Octane satellite image may have been picking up on areas of intensification before it was radar indicated. The areas of interest lie on the Lincoln, Cheyenne, Kiowa county lines and Lincoln, Kiowa lines as seen in the upper left image below. There is a gradient between the yellow and blue which identifies areas of divergence. The bottom right image is the radar showing that there are cells in the area.

This next image shows the probsevere predictability at the time of the above image. Note the values, especially on the prob hail (upper right)

The next image below shows that the probsevere values actually did increase in under 10 minutes on ProbSevere (Top Left and Prob Hail Top Right) The intensification could be from locally enhanced wind shear as Octane shows convection developing locations of strong shear in the localized areas of divergence aloft. It will be interesting to see if this trend continues throughout the week.

-Tornader

Monday 6/12 Initial Post

Posted in NUCAPS, OCTANE Speed Sandwich, SPG2023 on June 12, 2023 by Kevin Thiel.

Lots of products to look at and test. It’s a daunting task to know if you are looking at everything enough and in the correct way.

Appreciate the interaction with the developers and the openness to questions.

Below is a quick screen capture of the 6/12 19z 0hr NUCAPS MUCAPE (image) with the 19z 0 hour RAP40 MUCAPE contours. The developer mentioned that NUCAPS was good at depicting gradients but in this instance the gradient in the image is more smoothed than the RAP data while also being much less value than the RAP data. This raises questions on which analysis is best? Why? Is that same reasoning valid across the entire domain?

I would like to see observational data used as check point against model initialization. Where could larger errors in the model initialization raise questions about future forecasts. Asking the operational forecaster to quality control initial conditions has been a common ‘task’ assigned to maintaining situational awareness. I would like to see computers help with that task.

Quick update. Captured this image in the OCTANE data of an ongoing storm (likely supercell) in far NE New Mexico. The narrow corridor of light wind speeds (circled in white) matches my conceptual model of where the forward flank outflow boundary would be located. If this is the correct interpretation I think it would be very useful application in warning operations.

-jbm

Day 1 Review of Products & Operational Applications

Posted in NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, SPG2023 on June 12, 2023 by Kevin Thiel.

OCTANE-Direction

Distinguish different air masses when they are characterized by different advection regimes
- Stable cloud streets in magenta (Figure 1)
- Agitated Cu and deep, moist convection in yellow/green (Figure 1)
Locate boundaries
- Identify areas of convergence based on the depicted flow directions
Suggestion: it would be great to be able to sample the cardinal direction (i.e. NW, SE) in AWIPS in addition to the direction already given in degrees

Figure 1

NUCAPS & PHS

Attempts at convective initiation failed over Guadalupe County and De Baca County… but why? Isobaric analysis revealed supportive dynamics for ascent south of the already-occurring convection.
- 700 mb relative humidity and 850 mb humidity data (Figure 2) reveal a sharp moisture gradient across northeastern New Mexico
  - SPC 850 mb Td mesoanalysis verifies this (Figure 3)
- Dry air was already moving across both counties from the west and was progged to continue over the next few hours, thus hindering convective initiation

Figure 2

Figure 3

– Vort Max

6/12 Observations from ABQ CWA

Posted in LightningCast, NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on June 12, 2023 by Kevin Thiel.

OCTANE

Have knots abbreviated as “KTS” instead of “KN”

Change direction of movement from to lettered degrees instead of a numerical value

This product does help me become more aware, in realtime of the winds vertically. However, not entirely sure how to adapt this into my forecasting routine yet.

NUCAPS

Great to see the better sampling/readout of the data compared to what it was 2-3 years ago

The parcel count is a great way to help me gauge the validity of the data (confidence in how accurate it is)

Overlaying a NUCAPS forecast field with the parcel count allows me to sample what the field has and what the parcel count is so I can have more of less confidence in the data

No less than six hours for operational needs. 9 hours might be the perfect duration. I usually don’t use hourly data much beyond 9 hours due to my lack of confidence in the reliability of the data.

Hourly data is very nice. Half hour spacing is a bit too much data for that duration.
-Something to consider is could there be half hour spacing in the data for the first three hours? However I don’t know if that would be enough of a benefit to use.

I would use the 700-500mb lapse rates, ML CAPE, temp and dew point, and parcel count most often.

PHS

Very easy to look at; very smooth data

Didn’t have much time to look at the data

Lightningcast

Noticed on a well defined supercell the lightning probability is not over 80% despite lightning ongoing. Does the program cap at 75-80%?
-Have GLM ligthning data displayed too

Otherwise this does help draw my eye to where lightning could occur in the near future.

Prob Severe

Didn’t have time to look at it much. Did notice the storm in eastern CWA had higher values for version 3 than for version 2

– Rainman

HGX Convection impacting the Car and Truck Show in Burton, TX

Posted in DSS, GLM, LightningCast, NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on June 8, 2023 by Kevin Thiel.

Initial setup for the HGX vicinity showed several cells to the north and east of the DSS site, propagating southeastward. The strongest cell, pictured below, had a PSv3 of 73%, while PSv2 remained as 56%.

We issued a warning for a northern cell moving into the CWA into Madison county, based on a -70C cloud top brightness temp and PSv3 total prob over 70% (had been climbing from the 50s fairly steadily). But the cloud top shear noted by Octane was not strong (~20-25 kts), so the warning was very borderline. Just a couple scans later, it lost most of its texture on the vis imagery and lost its shear in the Octane direction product. Cloud tops warmed a bit as well.

00H NUCAPS-Forecast (NF) is showing moderate CAPE now (1st image below), which may help explain the messy sub-severe multicell clusters, but the forecast valid at 02z this evening shows a resurgence in the CWA (2nd image below).

Looking to our NW, one of the stronger cells is outside our CWA, but the Octane direction is showing good cloud top diffluence.

The PHS SCP forecast valid at 20z looks to be around 2-4 over our area, although this doesn’t match well with the SPC meso page SCP, which focuses high values W of our CWA.

The 21z PHS MUCAPE (15z run) looks like it has insane values of 6000-7000 J/kg near the coast and just offshore. This is much higher than the SPC meso page, showing 3000-4000 J/kg at most.

Looking at the optimal application of LightningCast, it seems that the point-based meteogram would work best for CI and in situ developing convection, versus storms propagating into the area. In our case here, at the DSS site, the point-based LC probs are low, suggesting little concern. But we can see from the GLM FED data that there are mature cells with lightning just to the NE that will probably move near the site in the next hour, which certainly poses a safety concern.

The NUCAPS sounding near Victoria (far SW CWA) showed a lot of CAPE and DCAPE, but a rather dry profile. This is confirmed by WV imagery over much of far S TX.

22z PHS Composite Reflectivity (above image) compared to 22z MRMS Composite Reflectivity (below image ) depicting PHS struggling on timing as the cluster of thunderstorms propagate from northwest to southeast.

Late in the event, this cell is showing slow strengthening on PS — currently both v3 and v2 have 40% total.

– Edgar and Harvey Specter

Severe Storms over Central Texas.

Posted in NUCAPS, OCTANE Speed Sandwich, ProbSevere, SPG2023 on June 8, 2023 by Kevin Thiel.

Storms over northern Bexar and southern Comal have had hail up to golfball size reported. This is in good agreement with the MESH signature. Additionally, Prob hail for both v3 and v2 are up over 80%, so in good agreement with the algorithm.

Animation of storms with the latest OCTANE. Looks like storm top divergence can be inferred from 70 kt anvil level winds to the south and 30 knot winds to the northwest. Would equate to strong divergence aloft and indicative of a severe storm.

The 08Z Pass of NUCAPS shows a rather impressive PWAT/Moisture gradient this morning, which would likely lead to increased storm chances along the theta gradient over the Hill Country and stretching eastward into the I-35 Corridor. The gradient ranged from 1.25” over the Coastal Plains to .50” over the Edwards Plateau and western EWX CWA.

This ties in nicely with the MLCAPE available this morning.

Storms going up in a weaker shear environment with a rainbow color distribution all around the storm from the OCTANE direction window. Very interesting. You may actually be able to infer the type of storm/environmental conditions just based on OCTANE direction depending on the situation.

– Satellite Steve, StormofCentury , Bolt

CHS OCTANE Orphan Anvils

Posted in OCTANE Speed Sandwich, SPG2023 on June 8, 2023 by Kevin Thiel.

While watching for convective initiation over the Charleston CWA, we noticed that the deepest convection over land started to produce orphan anvils; two of them during this loop. It made us curious if we could see any precursor in the OCTANE Speed Sandwich RGB to a developing orphan anvil. At the typical color bar range of 0-200, it was minimally visible, but as we shrunk the range, a precursor became more evident. The example here has a range of 0-75. Note the cell in the center of the screen. At the beginning of the loop an orangish reddish color can be seen just before the orphan anvil develops, then a more noticeable color enhancement can be seen as another anvil is about to be orphaned. From a forecaster standpoint, knowing anvils are about to be orphaned can be helpful to know that a particular cell is not likely to intensify and will probably diminish. Although orphan anvils can be seen with the OCTANE Speed Sandwich, orphan anvils still may be better seen in day cloud phase or day cloud type RGBs.

OCTANE Speed Sandwich loop of two orphan anvils developing.

– Burton Guster & Displar

MAF Convection

Posted in DSS, LightningCast, NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on June 7, 2023 by Kevin Thiel.

Convection has been slow to initiate in W TX, but we’re finally seeing some vertical extension and greater texture in the CU field on the NE side of the mountains. LightningCast is now showing higher probabilities in this area, after several scans of sub-50% contours.

We are seeing good destabilization. The PHS MUCAPE compares quite well to the SPC mesoanalysis.

LightningCast probabilities continue to climb, and we’re finally seeing a few flashes on GLM imagery.

Our LightningCast meteograms are finally showing some higher probs in the next hour near our DSS site in Fort Stockton.

We’re now seeing more defined features in the Octane imagery, including cloud top divergence signals and cooler brightness temps, down to -63C. But our ProbSevere markers remain low.

Looking at the NUCAPS-Forecast initialization at 19z, the mid level lapse rates are lower in areas NE of the higher terrain, where convection has been a bit slower to strengthen, as compared to the storms to our SW over Mexico, where MLLRs are higher.

The new TPW imagery from NUCAPS shows well the delineation of the moist air to the E and drier air to the W.

The PHS SHiP pattern looks good, but its magnitudes appear way off, compared to the SPC meso page and how SHiP is calculated.

Hail probs are exceeding 80% now on ProbSevere, although our GLM lightning is rather low! Interesting how assumed large hail presence doesn’t necessarily equate to classic charge separation that would prompt high electrification.

21z 700-500mb comparison of SPC Meso (top) vs 21z NUCAPS-Forecast (bottom)
– Some differences in lapse rates between the two, with NUCAPS about .5-1°C/km lower than SPC Meso page.

ProbSevere, Octane, and IR imagery supports warning issuances for Reeves and Pecos counties.

With the warning now out for Reeves and Jeff Davis counties, this storm continues to exhibit high hail probabilities on PSv3.

Up to 120 kts of ST divergence with the warned cell (at about 50 kft).

Interesting how ProbSevere identifies objects. There appears to be 3 separate updrafts in Pecos county, however PS is seeing one object.

– Edgar and StormofCentury

Examination of LightningCast and OCTANE in Idaho and Oregon

Posted in DSS, LightningCast, OCTANE Speed Sandwich, PHSnMWnABI, SPG2023 on June 7, 2023 by Kevin Thiel.

Near the Idaho/Oregon border, we observed splitting cells on the afternoon of Wednesday, June 7. We believe we were able to see the first hints of this process get underway with the help of the OCTANE product. Subtle gradients were observed on the left side of the main storm prior to the ultimate cell merger.

In the image on page 2, we see a nice comparison using LightningCast between an environment characterized by cirrus contamination vs an environment that was not contaminated. On the eastern side of the CWA that was characterized by cirrus contamination, LightningCast probabilities peaked at 50% on a storm that ultimately produced lightning. In contrast, two thunderstorms to the west (developing in a clear, cloud-free environment) both saw LightningCast values exceed 80% on two storms that ultimately produced lightning.

Above, we see perhaps the first instances of a splitting cell in progress, and OCTANE helped give us a first indication of the split (upper left in particular)

Above: LightningCast Meteogram as of 2053z, depicting a small trend upwards, albeit extremely minimal, within the next 60 minutes for some lightning impacting the American Aquarium at Hayden Beverage in Boise (DSS location).

Above: 21z PHS shows development of convection in Owyhee and Twin Falls counties (southern BOI CWA) depicted by a red box; however, the 4 Panel Situational Awareness is indicating that doesn’t seem to be the case, with mere cirrus cloud development. Perhaps the timing is off?

Above: On the other hand, PHS is doing a fairly good job depicting the convection just east of the DSS site. Currently (almost 22z), a few decent cells depicted by ProbSeverev3 (right around 15-18% probability, where MESH values are just over 0.50”)

Above: 2123z: LightningCast indicating just above 50% probability of lightning within the next hour yet the Meteogram is well below 20% for the GOES East reading. It is suspected that this is because the AWIPS readout is Plax-Corrected, whereas the Grafana Meteogram may not be?

Just after 22z, Grafana Meteogram (above) shows GOES East ProbSevere Lightning to be 67%. This latency further aids in the belief that the Meteogram is not Plax-Corrected.

As of 2220z, downward trend displayed with regards to the Grafana Meteogram (topped at 70%, now showing 54%). This is indicative of the cells east of Boise (DSS area) initially showing signs of weakening…HOWEVER…

Things are starting to get juicy at 2224z with ProbSevere v3 showing the cell south of Idaho City has increased to 36% probability (below).

– Bolt and Harvey Specter

Albuquerque HWT

Posted in NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, SPG2023 on June 7, 2023 by Kevin Thiel.

Storms are exhibiting some decent shearing aloft over NW New Mexico when comparing to NE New Mexico. Something I might not have noticed had I not had this product as I don’t always have time to go into the SPC mesoanalysis and check various levels of shear values. The 0-8km shear values are in the 40-50 kt range, in agreement with the range of values noted on the speed shear values of OCTANE. See below.

PHS really doing a nice job of pointing out peak areas of MUCAPE and where storms will likely develop. Decent scale and resolution results in some good quality comparisons with various other products. This is over the southern ABQ CWA.

Forecast Layer Comp Refl 21Z

Forecast MUCAPE 21Z

Forecast MUCAPE 23Z – Also, noting a sharp gradient in MUCAPE values as convection strengthens over east-central New Mexico late this afternoon into the early evening hours. We will have to see how this plays out.

MUCAPE values seem a bit higher than they should be when compared with the MLCAPE values at the same times over New Mexico. I’m not exactly sure why the values are so high, but the forecast RAP values for the same time frame appear to be notably more displaced to the east and lower.

Example below from forecasted time 02Z.

The 6 hour forecast at 21z of PHS 0-6 km Bulk Shear (first image) is compared against the 21z SPC Mesoanalysis (second image). Overall, the PHS forecast did quite well over New Mexico. There is generally little to no shear across the state except for near the Four Corners in the northwest and far southeastern New Mexico. The values are reasonable in these areas as well, around 16 m/s for PHS which fits in with the over 30 knot SPC values.These differences can be noted in the convection occurring as well (seen in the SPC image). Mainly isolated cellular over central NM, but showing more organization in the areas of higher shear.

-Satellite Steve and Burton Guster

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Spring Experiments & Beyond

Category: OCTANE Speed Sandwich